In recent years, businesses offering rapid processing and printing of color print film, the "One Hour Photo" services, have proliferated. The commercial availability of the automated machines used for this rapid processing and printing, and their comparatively low cost have enabled many small business owners to enter the field, so that the photofinishing business is no longer confined to a few major commercial photo laboratories.
The processing equipment uses a variety of chemicals for film processing and printing. Each chemical is kept in a separate tank or reservoir from which it is pumped into the processing area of the machine at an appropriate time. After the specified time period for the chemical to be in contact with the film or print being processed, the chemical is pumped back to its storage tank, for reuse. The manufacturers supply directions as to the working life of each agent, and directions as how to replenish the chemicals after a specified usage. In the course of processing and storage of the chemicals, various types of particulate matter, debris such as film fragments or paper fragments, aggregates of photographic chemicals, dirt, dust, or microorganisms such as algae or bacteria may contaminate the chemicals and their storage tanks. The presence of contaminants can damage film or prints being processed by scratching negatives or prints, causing losses that may require reprocessing or retouching, assuming such damage can be remedied. Contaminants may decrease the efficacy of the chemicals themselves, or clog up the processing equipment, resulting in lost time spent to clean the equipment.
Although disposable filters are available, their replacement cost over time can be significant. The cumulative disposal of filters also has an environmental impact.
Nondisposable filters utilized in this equipment are difficult to reuse because the filtration material is mounted on the inside of the filter. Consequently, these filters are difficult to clean thoroughly. Some of the materials used to manufacture these filters are subject to being washed off or damaged when subjected to cleaning, thus preventing their reuse.
One commercially available product employs a stainless steel filter tube that is fitted over a frame manufactured from an extruded plastic material. Although this filter fits on the frame like a sleeve, it is difficult to clean and maneuver into a good (i.e., fluid-tight) fit within the apparatus.
Thus there is a need for a filtration device having a filter that in made of a reusable filtration material that is reusable, that won't be washed off of its support matrix during cleaning, and that won't be damaged during cleaning. Further, the filtration device should be made of materials capable of withstanding the physical conditions, including pressures, temperatures and flow rates, and chemical conditions of the environment of photographic processing chemicals in automated processing machines.